Polyfunctional polyalkyleneglycols and their polyquaternary ammonium salts



United States Patent 7 Claims ABSTRACT OF THE DISCLOSURE Polyfunctionalpolyalkyleneglycols and their polyquaternary ammonium salts which arederived from ethylenediamine tetraacetic acid,alkylaminopropylamine-N,N',N- trisacetic acid, polyamino alcohols,N-methylgluconamine (or N-methylglucamine) and contain at least 6alkyleneglycol units per molecule are used to advantage to increase thesensitivity of photographic emulsions which have already been sensitizedto their optimum or near optimum with chemical sensitizers.

This is a divisional application of US. patent application Ser. No.201,788, Sensitizers for Photographic Silver Halide Emulsions, filedJune 12, 1962, now Patent 3,253,- 919, issued May 3l, 1966.

This invention relates to photographic silver halide emulsions, and moreparticularly, to an improved means for sensitizing such photographicsilver halide emulsions.

A number of methods have been previously described for increasing thesensitivity of photographic silver halide emulsions other than methodsof optical or spectral sensitization which involve the incorporation ofcertain colored compounds or dyes in the emulsions. The incorporation ofsuch dyes in the emulsions increases or extends the optical range ofsensitivity and for this reason such dyes are commonly referred to asoptical or spectral sensitizing dyes. It is also Well known to increasethe sensitivity of photographic emulsions by the addition of sulfurcompounds capable of reacting with silver salts to form silver sulfide,or with reducing agents (compounds of these types are also naturallypresent in gelatin) or with salts of gold or other noble metals, or withcombinations of two or more of the aforementioned compounds generallyknown as chemical sensitizers. Such chemical sensitizers are believed toreact with the silver halide to form, on the surface of the silverhalide minute amounts of silver sulfide or of silver or of other noblemetals, and these processes are capable of increasing the sensitivity ofdeveloping-out emulsions by a very large factor. However, there is adefinite limit beyond which further additions of chemical sensitizers orof further digestion with the sensitzer present, merely increases fog ofthe photographic emulsion with constant or decreasing emulsion speed.

We have now found a means of further increasing the sensitivity ofphotographic emulsions which may be applied even through the ordinaryprocesses of chemical sensitization have been carried to the effectivelimit of the photographic emulsion in question. Our process is to bedistinguished from hypersensitizaton which is produced by bathing afinished coating with water or with solutions of ammonia, amines orsilver salts. Such processes act primarily on optically sensitizedphotographic emulsions and tend to increase the free silver ionconcentration of the emulsion and greatly diminish its stability. Ourprocess is also to be distinguished from hypersensitizaton by mercuryvapor which gives a transitory effect that is lost on storage of thefilm. The compounds used in our invention do not appear to be chemicalsensitizers in the usual sense, since they increase speed by theirpresence during exposure and processing, and require no digestion withthe photographic emulsions to produce an increase in speed nor doestheir chemistry indicate that they are likely to react with silverhalide under normal emulsion conditions.

The novel sensitizers of our invention, the polyfunctionalpolyalkyleneglycol compounds and their polyquaternary ammonium saltswhich are derived from ethylcnediamine tetraacetic acid,alkylaminopropylamine-N,N',N'-trisacetic acid, polyamino alcohols,N-methylgluconamine (or N- methyl-glucamine) and contain at least sixalkyleneglycol units per molecule, are unique in that the effectsproduced are additive in photographic emulsions which have already beensensitized to their optimum or near optimum with conventional chemicalsensitizers, such as labile sulfur compounds. The novel sensitizers: ofour invention, however, can be used to sensitize photographic silverhalide emulsions containing no other sensitizers if desired. The novelsensitizers of our invention are not strictly chemical sensitizers sincechemical sensitizers do not generally provide the additive effects ofthe type mentioned.

it is therefore an object of our invention to provide photographicemulsions that have been sensitized with our qpolyfunctionalpolyalkyleneglycol sensitizer compounds or polyquaternary ammonium saltsderived from them.

It is a further object of our invention to increase the lightsensitivity of ordinary photographic silver halide emulsions which havebeen sensitized with chemical sensitizers, such as compounds containinglabile sulfur atoms or gold containing compounds without increases infog which might seriously effect the usefulness of the emulsions.

A further object is to provide a novel class of sensitizers which arereadily dissolved in Water and added to gelatino-silver halideemulsions.

A still further object is to provide a novel class of sensitizers whichwhen added to photographic silver halide emulsions, produce theirsensitizing effects without further digestion of the emulsion.

Other objects will become apparent from the following specification andclaims.

According to our invention the sensitivity of ordinary high speed silverhalide emulsions chemically sensitized in the conventional way issubstantially increased by the incorporation of our polyfunctionalpolyalkyleneglycol sensitizers or polyquaternary ammonium salts derivedfrom them. Our novel sensitizers are particularly useful since they havea high degree of water solubility and are readily incorporated in thesilver halide emulsions in sensitizing amounts.

Included in the compounds of our invention are those having the formula:

in which 1 represents an integer of from 2 to 10; Z represents in whichR, is an :alkyl group having from 1 to 20 carbon atoms such as methyl,ethyl, butyl, octyl, decyl, dodecyl, pentadecyl, heptadecyl, octadecyl,phytyl, etc., and X" is an acid anion, such as chloride, bromide,perchlorate, a lower alkylsulfonate, e.g., methylsulfonate,ethylsulfonate, propylsulfonate, butylsulfonate, etc., an arylsulfonate,e.g., p-toluenesulfonate, benzenesulfonate,

3 etc.; A A and A each represents a polyalkylene oxide chain derivativeof a short alkyl chain having from 2 to 3 carbon atoms and containing an-OH or a i -C-OH group in which the number of alkylene oxide units maybe the same or different and in which the alkylene oxide units may havefrom 2 to 3 carbon atoms per unit, such as ethylene or propylene andsuch that when the alkylene oxide units have 3 carbon atoms, Zrepresents a group; and B represents an alkyl group having from 1 to 20carbon atoms, such as methyl, ethyl, propyl, butyl, heptyl, octyl,decyl, dodecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, phytyl,etc., or may be the same as A1, A2 01' A3.

in Which Z is as defined previously, and n is an integer such that theaverage value of n is from 8 to 100;

in which R represents an alkyl group having from 1 to 20 carbon atoms,such as methyl, ethyl, propyl, butyl, hexyl, octyl, dodecyl, pentadecyl,hexadecyl, phytyl, etc.; m is an integer from 2 to 3; q and q eachrepresent an integer such that the total of the 4 qs and q has anaverage value of from 6 to 100; Y represents a hydroxyl group, a

group or a group in which R R and R each represents an alkyl grouphaving from 1 to 4 carbon atoms, such as methyl, ethyl, propyl, butyl,etc., and X represents an acid anion as described previously, such thatwhen m is the integer 3, Y represents a group of a /R2 N R X group.

Included among our sensitizers of Formula I are those of Formulas IV, V,VI, and VII which follow.

in which n n n and n, are each integers which may be the same ordifferent, such that the total of n m n 11 has an average value of from6 to 100, and Z is as defined previously.

ornonmn -n in which n n n 11 and Z are as defined previously,

in which n n n m and Z are as defined previously, and

VII R CH3 CH3 (CH2CH2O)n H l i cun rv 11(0 CHZCHZLJ,

(K n (CHzCHzO) u H in which R represents an alkyl group having from 1 to20 carbon atoms such as methyl, ethyl, propyl, butyl, heptyl, octyl,decyl, dodecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, phytyl,etc.; n n and n each represent an integer such that the sum of n +n +nhas an average value of from 8 to and p and X are as describedpreviously.

Our sensitizers of Formula III include those of the following formula:

in which Y is as defined previously and n is an integer that can be thesame or different from n n n and 11 such that the total of n +n +n +n +nhas an average value in the range from 6 to 100.

Included among the polyfunctional polyethyleneglycol (i.e.,polyfunctional PEG) sensitizing compounds and their polyquaternary saltsare the following representative examples used to illustrate but notlimit our invention.

Sensitizer Sensitizer name number 1.- Ethylenediamiue tetraaceticacid-tetrakis (nouaethyleno glycol ester) or polymeric producttherefrom.

polyethyleneglycol 977 (Average of 22.2 ethylene oxide units permolecule).

9 1-trimethylammonium-3,6,9'triaza-3,3,6,6,9,9-hexamethylundeeyl etherof polyethylene-glycol-977-tetrakis (ptoluencsulfonate) 1ON'lauroy1-N-methylgluconamine polyethylene-glycol-264 (Average of 6ethylene oxide units per molecule).

11 N-lauroylN-methylgluconamiue pol yethylene-glyeol-264-tetrakis(methanesullonate).

l2 N-lauroyl-N-methylgluconamiue polyethylene-glycol-792 tetrakismethanesulfonate (Average of 18 ethylene oxide units per molecule).N-lauroyl-N-methylglueonamine polyethylene-glyc0l-792 tetrakis(pyridinium methanesulfonate). N-lauroyl-N-methylglueonaminepolyethylene-glycol 264 tetrakis(pyridiniu1n methanesulfonate) Alsoincluded among the sensitizers of our invention are the polyfunctionalpolypropyleneglycol sensitizers and the polyquaternary ammonium saltsderived from them as defined by the Formulas I and III.

In general the polyalkyleneglycol derivatives are prepared by reactingthe amino alcohols and acids with ethylene oxide (or propylene oxide) inthe presence of catalysts, such as Lewis-type acids, tertiary amines,acids or inorganic bases.

However, the addition of polyethylene glycol (or polypropylene glycol)chains to a polycarboxyacid or amide can most conveniently beaccomplished by reacting the polycarboxy acid or amide with the desiredpolyethyleneglycol, such as nonaethyleneglycol, using an acid catalyst.p-Xylene is used to azeotrope off the water formed in the reaction andis collected in a Dean-Stark trap. The preparation of ethylenediaminetetraacetic acidtetrakis (nonaethyleneglycol ester) was accomplished inthis manner. It is understood that this product may con tain a monomerictype unit, or may polymerize to give very large molecules containingmany ester or amide functions. Epoxides, such as propylene oxide, may beadded to acids and also amides under high temperatures and pressures inan autoclave with the usual catalyst, if desired. Monomers and polymersmay form in this reaction.

The polyethyleneglycol or polyalkylene oxide derivatives of polycarboxyacids, alcohols, or amides are further converted to thepolymethanesulfonates, or hydroxyhalides, and the resulting polyintermediates are quaternized. The polysulfonate esters are formed byreaction of the polyhydroxy compounds with alkyl or aryl sulfonylchlorides in pyridine; or a polyhydroxy halide may be readily preparedby reaction of the polyglycols with epihalohydrins. The esters andhalides readily quaternize with tertiary bases, such as trialkylaminesor tertiary nitrogen heterocyclics. Pyridine has been found a superiorquaternizing agent for our sensitizing compounds. If desired, thesulfonate or halide anion may be converted to the perchlorate anion withsodium perchlorate.

The molecular weight of our sensitizing compounds can vary over ratherwide ranges because of the diiferent number of alkylene oxide units,such as ethylene oxide or propylene oxide units that they may have permolecule. The alkylene oxide chains on a given molecule of thesensitizers may be of equal or varying lengths. The sensitizingcompounds of our invention have molecules with a total of from 6 to 100alkylene oxide units per molecule, and the total molecular weight of thealkylene oxide units in a molecule may vary from about 264 to about7200.

Our invention is still further illustrated by a descrip tion of thepreparations of the representative sensitizing compounds.

Sensitizer 1 Ethylenediamine tetraacetic acid, 14.6 g. (0.05 mole) wasadded to 150 ml. of p-xylene. Carbowax 400, a Carbide and Carbon Co.polyethylene glycol product, 80 g. (0.20 mole), was added along withhalf a milliliter of concentrated sulfuric acid. The resulting slurrywas stirred vigorously while heating to reflux in a flask provided witha Dean-Stark trap and condenser. After 16 hours, the theoretical amountof water had been collected. The dark mixture was treated withdecolorizing charcoal and filtered through a diatomaceous silica filterbed. The solvent was removed on the steam bath under vacuum leaving 70g. of a dark, viscous oil which dissolved to a clear solution in water.

Sensitizer 2 Forty-one grams (0.10 mole) oftetrahydroxyethylethylenediamine PEG-176 with 2 drops of borontrifluoride-ether complex (catalyst) was added to a flask equipped witha stirrer, a Dry-Ice acetone condenser, and gas inlet. The flask washeated to 60 C. on a water bath, and 54 g. (1.2 moles) of ethylene oxidewas bubbled into the reaction mixture under the surface of the liquid.After 6 hours, the mixture was heated on the steam bath to removecatalyst and unreacted ethylene oxide leaving a dark yellow oil weighing95 g. The oil was dissolved in methanol, treated with decolorizingcharcoal and diatomaceous filter aid and filtered. After removal ofsolvent under vacuum, 83 g. of a pale orange colored viscous oilremained which was soluble in Water.

Sensitizer 3 The same process used for making Sensitizer 2 was used but110.5 g. (2.5 moles) of ethylene oxide was reacted during 4 hours with46.4 g. (0.20 mole) of tetrahydroxyethylethylenediamine in the presenceof the catalyst. After treatment with decolorizing charcoal and filteraid, 132.5 g. of a light-brown viscous syrup was obtained.

Sensitizer 4 This sensitizer was prepared as was Sensitizer 2 but by thereaction of 46.4 g. (0.20 mole) of tetrahydroxyethylethylenediamine withg. (1.8 mole) of ethylene oxide in the presence of three drops of thecatalyst over a period of 5 hours. Following treatment with decolorizingcharcoal and filter aid, filtration and removal of excess solvent undervacuum, 85.4 g. of Sensitizer 4, a dark viscous oil, was obtained.

Sensitizer 5 Ten grams of tetrahydroxyethylethylenediamine PEG- 176 and9.1 g. of methyl p-toluenesulfonate were added together with stirring. Amild exothermic reaction raised the temperature to 58 C. The dark red,viscous liquid was heated on the steam bath for an additional two hoursto insure complete reaction. The orange colored syrup was then slurriedtwice with hot benzene to remove unreacted starting material. The oilwas dissolved. in ethanol, heated with decolorizing charcoal andfiltered through a filter bed formed with diatomaceous silica. Thesolvent was removed on the steam bath under vacuum, giving 11.5 g. of aviscous, water-soluble oil.

Sensitizer 6 HeptadecylaminopropylaminoN,N',N-trispolyethyleneglycol-1320 (i.e., Armour and Co.s Ethoduomeen T/40), was a dark, viscous syrup as obtained. It was dissolved in acetone,heated with decolorizing charcoal and filtered with diatomaceous silicafilter aid through a filter bed, giving a clear, orange syrup. Theexcess solvent was removed on the steam bath under vacuum, leaving 19.8g. of an orange syrup which partially solidified upon cool- 1ng.

To this product was added 4.5 g. of methyl p-toluenesulfonate and themixture stirred while a mild exothermic reaction took place. After thishad subsided, the mixture was heated on the steam bath for 4 hours. Theproduct was slurried with ether several times, and the ether solutiondecanted each time. The remaining traces of ether were removed on asteam bath under vacuum, giving a viscous oil.

Sensitizer 7 1 dimethylamino-3,6,9-trimethy1 3,6,9 triazundecanol-l, 26g. 0.10 mole), was heated on the steam bath in a flask equipped with aDry-Ice acetone condenser, stirrer, and submerged gas inlet tube. Aftertwo and onehalf hours of ethylene oxide gas addition, and after removalof the unreacted gas on the steam bath under vacuum, the oil weighed79.5 g. A weight increase of 53.5 g. indicated that 12.1 moles (PEG-525)ethylene oxide had reacted with the amino alcohol.

Sensitizer 8 Forty grams of the above ethylene oxide addition productcontaining 12.1 moles of ethylene oxide were heated and reacted underthe same conditions as above. After approximately one and one-half hoursof addition, 22.5 g. of ethylene oxide by weight were added, giving anoil which now contained 22.2 moles of ethylene oxide (PEG- 977) per moleof amino alcohol. For a lighter-colored product, the oil was dissolvedin methanol, decolorizing charcoal added, and the solution filteredthrough a diatomaceous silica filter bed. Concentration of the filtrateunder vacuum on the steam bath gave 60 g. of a dark, water-soluble oil.

Sensitizer 9 The above polyethyleneglycol addition product, 12.4 g.(0.01 mole), and 8.6 g. (0.046 mole) of methyl ptoluenesulfonate wereheated together on the steam bath for two hours. The resulting oil wasslurried with ether several times to remove traces of unreactedsulfonate ester. The excess solvent was removed on the steam bath undervacuum. Twelve grams of a dark, viscous water-soluble oil was obtained.

Sensitizer 10 Ethylene oxide 26.5 g. (0.60 mole) was added to 37.7 g.(0.10 mole) of N-lauroyl-N-methylgluconamine in the presence of 3 dropsof the catalyst as described in the preceding examples. The ethyleneoxide was added over a period of about 4 hours. After purification,there remained 64.2 g. of a viscous orange colored oil soluble in water.

Sensitizer 11 N methyl-N-lauroylgluconamine PEG 264, 25.0 g. (0.04mole), was dissolved in pyridine and chilled to C. Methane sulfonylchloride, 17.2 g. (0.16 mole), was slowly added through a droppingfunnel while the temperature of the reaction mixture was held at 010 C.After stirring for two hours, the mixture was allowed to warm up to roomtemperature. The slurry was acidified with cold hydrochloric acid (1:1)and saturated with sodium chloride. The acidic solution was extractedthree times with 200 ml. of warm benzene, and the extract was dried oversodium sulfite. After treatment with decolorizing charcoal, the benzenewas removed on a steam bath under vacuum leaving 24 g. of a dark viscousorange colored syrup.

Sensitizer 12 N-lauroyl-N-methylgluconamine PEG-792 was prepared in theusual manner by the addition of ethylene oxide in the presence of aboron trifluoride catalyst at 85. Twenty-three grams of this additionproduct was dissolved in 100 ml. of dry pyridine, chilled to 0, andrnethanesulfonyl chloride was added with rapid stirring, keeping thetemperature below The slurry was stirred at 0 for two hours, then atroom temperature for two hours. The slurry was acidified, saturated withsodium chloride and extracted with three 200-ml. portions of warmbenzene. Concentration of the extracts under vacuum on the steam bathgave 16.5 g. of an orange oil.

Sensitizer 13 The above tetrakis methanesulfonate ester, 16.5 g., 50 ml.of pyridine and ml. of ethanol were refluxed for 1 /2 hours. The excesspyridine was removed under vacuum on the steam bath. The residual oilwas dissolved in methanol and precipitated with ether. The ether wasdecanted and the procedure repeated twice. The oil was then dissolved inmethanol, treated with decolorizing charcoal, the solution was filteredthrough a diatomaceous silica filter bed, and the solution concentrated.The tetraquaternary salt was isolated as 15.4 g. of a yellow, viscous,water-soluble oil.

Sensitizer 14 N methyl N lauroylgluconamine PEG 264-tetrakis(methanesulfonate), 10 g. and 25 ml. of pyridine were refluxed togetherfor 1 /2 hours. The excess pyridine was relieved on the steam bath undervacuum. The oil was dissolved in 10 ml. ethanol and precipitated outwith ether. The ether was decanted and the process repeated two moretimes removing all traces of solvent and excess pyridine under vacuum onthe steam bath. Nine grams of an extremely viscous orange colored oilwas obtained which was readily soluble in water.

The compounds of our invention are added to ordinary photographic silverhalide emulsions for the purpose of increasing the sensitivity thereofas has been indicated above.

The preparation of photographic silver halide emulsions involves threeseparate operations:

(1) Emulsification and digestion of silver halide,

(2) The freeing of the emulsion of excess water soluble salts usually bywashing with Water, and

(3) The second digestion or after-ripening to obtain increased emulsionspeed or sensitivity.

Mees, The Theory of the Photographic Process, 1954.

The sensitizers of our invention can be added to the emulsion before thefinal digestion or after-ripening or they can be added immediately priorto coating. Our new photographic sensitizers are characterized by notrequiring any final digestion or after-ripening in order to obtainoptimum sensitivity.

The particular quantity of our sensitizer compound used in a givenemulsion will vary depending upon the effects desired, degree ofripening, silver content of the emulsion, etc. The amount used is alsodependent upon the particular stage at which the sensitizer is addedduring the preparation of the emulsion. Generally, from about mg. toabout 5 g. of our compounds per mole of silver halide are quite adequateto accomplish the desired sensitization.

Our sensitizers can be added to photographic emulsions using any of thewell known techniques in emulsion making. Generally these compounds aresoluble enough in water so that the required concentrations are readilyobtained. If an auxiliary solvent is needed, solvents such as ethanol,acetone, pyridine, etc., can be used.

It is apparent that the optimum amount of sensitizer compound neededwill vary somewhat from emulsion to emulsion and from sensitizer tosensitizer. The optimum amount for a given sensitizer can be determinedfor any particular emulsion by making a series of tests in which thequantity of our sensitizer is varied over a given range. Exposure of thetreated emulsion in a conventional photographic testing apparatus suchas an intensity scale sensitometer, followed by development, and imagedensity measurement, will reveal the most advantageous concentration forthat sensitizer in that particular emulsion. Such matters are wellunderstood by those skilled in the art.

The photographic emulsions used in practicing our in vention are of thedeveloping-out type.

The emulsions can be chemically sensitized :by any of the acceptedprocedures. The emulsions can be digested with naturally active gelatin,or sulfur compounds can be added such as those described in SheppardU.S. Patent 1,574,944, issued Mar. 2, 1926; Sheppard et al. U.S. Patent1,623,499, issued Apr. 5, 1927; and Sheppard et al. U.S. Patent2,410,689, issued Nov. 5, 1946.

The emulsions can also be treated with salts of the noble metals such asruthenium, rhodium, palladium, iridium, and platinum. Representativecompounds are ammonium chloropalladate, potassium chloroplatinate, andsodium chloropalladite, which are used for sensitizing in amounts belowthat which produces any substantial fog inhibition, as described inSmith and Trivelli U.S. Patent 2,448,060, issued Aug. 31, 1948, and asantifoggants in higher amounts, as described in Trivelli and Smith U.S.Patents 2,566,245, issued Aug. 28, 1951 and 2,566,263, issued Aug. 28,1951.

The emulsions can also be chemically sensitized with gold salts asdescribed in Waller et al. U.S. Patent 2,399,- 083, issued Apr. 23,1946, or stabilized with gold salts as described in Damschroder U.S.Patent 2,597,856, issued May 27, 1952, and Yutzy and Leermakers U.S.Patent 2,597,915, issued May 27, 1952. Suitable compounds are potassiumchloroaurite, potassium aurithiocyanate, potassium chloraurate, aurictrichloride and Z-aurosulfobenzothiazole methochloride.

The emulsions can also be chemically sensitized with reducing agentssuch as stannous salts (Carroll U.S. Patent 2,487,850, issued Nov. 15,1949), polyamines, such as diethylene triamine (Lowe and Jones U.S.Patent 2,518,698, issued Aug. 15, 1950), polyamines, such as spermine(Lowe and Allen U.S. Patent 2,521,925, issued Sept. 12, 1950), orbis(,B-aminoethyl) sulfide and its watersoluble salts (Lowe and JonesU.S. Patent 2,521,926, issued Sept. 12, 1950).

The emulsions can also be optically sensitized with cyanine andmerocyanine dyes, such as those described in Brooker U.S. Patents1,846,301, issued Feb. 23, 1932; 1,846,302, issued Feb. 23, 1932', and1,942,854, issued Jan. 9, 1934; White U.S. Patent 1,990,507, issued Feb.12, 1935; Brooker and White U.S. Patents 2,112,140, issued Mar. 22,1938; 2,165,338, issued July 11, 1939; 2,493,747, issued Jan. 10, 1950;and 2,739,964, issued Mar. 27, 1956; Brooker and Keyes U.S. Patent2,493,748, issued Jan. 10, 1950; Sprague U.S. Patents 2,503,776, issuedApr. 11, 1950 and 2,519,001, issued Aug. 15, 1950; Heseltine and BrookerU.S. Patent 2,666,761, issued Jan. 19, 1954; Heseltine U.S. Patent2,734,900, issued Feb. 14, 1956; Van Lare U.S. Patent 2,739,149, issuedMar. 20, 1956; and Kodak Limited British Patent 450,958, accepted July15, 1936.

The emulsions can also be stabilized with the mercury compounds ofAllen, Byers and Murray U.S. Patent 2,728, 663, issued Dec. 27, 1955Carroll and Murray U.S. Patent 2,728,664, issued Dec. 27, 1955; andLeubner and Murray U.S. Patent 2,728,665, issued Dec. 27, 1955; thetriazoles of Heimbach and Kelly U.S. Patent 2,444,608, issued July 6,1948; the azaindenes of Heimbach and Kelly U.S. Patents 2,444,605, and2,444,606, issued July 6, 1948; Heimbach U.S. Patents 2,444,607, issuedJuly 6, 1948 and 2,450,397, issued Sept. 28, 1948; Heimbach and ClarkU.S. Patent 2,444,609, issued July 6, 1948; Allen and Reynolds U.S.Patents 2,713,541, issued July 19, 1955; and 2,743,181, issued Apr. 24,1956; Carroll and Beach U.S. Patent 2,716,062, issued Aug. 23, 1955Allen and Beilfuss U.S. Patent 2,735,769, issued Feb. 21, 1956',Reynolds and Sagal U.S. Patent 2,756,147, issued July 24, 1956; Allenand Sagura U.S. Patent 2,772,164, issued Nov. 27, 1956; and thosedisclosed by Birr in Z. wiss. Phot., vol. 47, 1952, p. 2-28; thedisulfides of Kodak Belgian Patent 569,317, issued July 31, 1958; thequaternary benzothiazolium compounds of Brooker and Stand U.S. Patent2,131,038, issued Sept. 27, 1938 or the polymethylenebis-benzothiazolium salts of Allen and Wilson U.S. Patent 2,694,716,issued Nov. 16, 1954 (e.g., decamethylene-bis-benzothiazoliumperchlorate); or the zinc and cadmium salts of Jones U.S. Patent2,839,405, issued June 17, 195.8; and the carboxymethylmercaptocompounds of Murray, Reynolds and Van Allan U.S. Patent 2,819,965,issued Jan. 14, 1958.

In the preparation of the silver halide dispersions employed forpreparing silver halide emulsions, there may be employed as thedispersing agent for the silver halide in its preparation, gelatin orsome other colloidal material such as colloidal abumin, a cellulosederivative, or a synthetic resin, for instance, a polyvinyl compound.Some colloids which may be used are polyvinyl alcohol or a hydrolyzedpolyvinyl acetate as described in Lowe U.S. Patent 2,286,215, issuedJune 16, 1942; a far hydrolyzed cellulose ester such as celluloseacetate hydrolyzed to an acetyl content of 19-26% as described in U.S.Patent 2,327,808 of Lowe and Clark, issued] Aug. 24, 1943; awater-soluble ethanolamine cellulose acetate as described in Yutzy U.S.Patent 2,322,085, issued June 15, 1943; a polyacrylamide having acombined acrylamide content of 30-60% and a specific viscosity of 025-15on an'irnidized polyacrylamide of like acrylamide content and viscosityas described in Lowe, Minsk and Kenyon U.S. Patent 2,541,474, issuedFeb. 13, 1961; zein as described in Lowe U.S. Patent 2,563,791, issuedAug. 7, 1961; a vinyl alcohol polymer containing urethane carboxylicacid groups of the type described in Unruh and Smith U.S. Patent2,768,154, issued Oct, 23, 1956; or containing cyano-acetyl groups suchas the vinyl alcohol-vinyl cyanoacetate copolymer as described in Unruh,Smith and Priest U.S. Patent 2,808,331, issued Oct. 1, 1957; or apolymeric material which results from polymerizing a protein or asaturated acylated protein with a monomer having a vinyl group asdescribed in U.S. Patent 2,852,- 382, of Illingsworth, Dann and Gates,issued Sept. 16, 1958.

Our emulsions may contain hydrop-hilic colloid plasticizers, hardeners,coating aids and other addenda as described in Beavers U.S. Ser. No.853,009, filed Nov. 16, 1959.

The sensitizing effects produced by our polyfunctional polyethyleneglycols and their polyquaternary salts when they were added to highspeed gelatino-silver halide emulsions is illustrated by the followingexample.

EXAMPLE 1 A high-speed gelatino-silver iodobromide emulsionpanchromatically sensitized with a cyanine dye was coated on a clearcellulose acetate support toyield a silver coverage of 430 mg. persquare foot and a gelatin coverage of 1080 mg. per square foot. Thismaterial served as a control. Identical coatings of this same emulsionwere made which were sensitized by adding our sensitizers in the amountsindicated in Table 1. A sample of the control coating and the coatingssensitized with sensitizer N0. 1 were given identical sensitometricexposures in an Eastman 1-B Sensitometer, given identical 5 minutesdevelopment in a developer having the formula:

Water about 125 F. (50 C.) cc 500 p-Methylaminophenol sulfate g 2.5Sodium sulfite (desiccated) g 30.0 Hydroquinone g. 2.5 Sodium metaborate-8H O g 10.0 Potassium bromide g 0.5

Water to make 1 liter.

then fixed by treating in a fixing bath having the formula:

Sodium thiosulfate g 240.0 Sodium sulfite (desiccated) g 15.0 Aceticacid 28% cc 48.0 Boric acid crystals g 7.8 Potassium alum g 15.0

Water to make 1 liter.

washed and dried. The optical densities of the developed images weremeasured with a densitometer and from these data relative speeds(photographic) were determined for each sample based on a speed of forthe control sample. The gammas and fog values were also determined foreach sample. This procedure was repeated with a separate control forcoatings sensitized with each of the sensitizers 2, 5, 6, 7, 9, 13 and14. The data obtained are listed in Table I.

TABLE I Silver halide Concentraemulsion tion of sensi- Fog in sensitizedtizer in Relative Gamma density with sensitizer grams/mole speed unitsnumber of silver 100 1. 18 16 0. 15 102 1. 12 16 0. 75 138 1. 22 3. 00182 1. 04 23 0 100 1. 38 16 3. 00 126 1. 38 l8 0 100 1. 48 l3 0. 102 1.57 13 3. 00 115 1. 52 15 0 100 1. 48 13 0. 15 151 1. 35 18 0. 75 240 1.43 21 3. O0 251 1. 27 27 0 100 1. l8 16 0. 15 105 1. 36 19 0 100 1. 0918 0. 15 100 1. 07 18 0. 75 126 1. 14 20 3. 00 126 1. 08 24 0 100 1. 2013 0. 15 166 1. 17 16 0. 75 269 1. 00 24 2. 25 316 1. 14 0 100 1. 28 130. 75 182 0. 91 32 These data show that high speed photographicemulsions are sensitized by the addition of representative members ofour polyfunctional polyethyleneglycol sensitizers and theirpolyquarternary salts up to relative speeds as high as 316 compared tothe control speed of 100. The amount of sensitization produced by agiven sensitizer depended upon the concentration of the sensitizer used.The optimum concentration of sensitizer can be determined similarly forother of our sensitizers in other silver halide emulsions.

Incorporation of our sensitizers in emulsions intended for colorphotography, for example, emulsions containing color-forming couplers oremulsions to be developed by solutions containing couplers or othercolor generating materials has indicated their utility therein.

Incorporation of our sensitizers in silver halide emulsions and coatedlayers designed for use in silver halide diffusion transfer processes ofthe type described in Rott US. Patent 2,532,014; Land US. Patents2,584,029 and 2,543,181; and in Yackel et al. US. Patent 3,020,155 gaveuseful black-and-white transfer systems.

Our sensitizers, when added to silver halide emulsions and coated layersdesigned for dye transfer color processes of the type described in YutzyUS. Patent 2,756,- 142, or in Whitrnore and Mader US. patent applicationSer. No. 734,191, filed May 9, 1958; or in dye developer transfer colorprocesses of the type described in Land US. Patents 2,559,643 and2,698,798; Land and Rogers Belgian Patents 554,933 and 554,934; and inInternational Polaroid Belgian Patents 554,212 and 554,935, producedcolor images of improved quality.

The effect of our new sensitizing compounds has been illustrated abovewith particular reference to ordinary high speed photographic silverbromoiodide emulsions, although it is to be understood that other silverhalide emulsions can also be employed to advantage. Our sensitizers canbe used in emulsions which are acidic in character or in emulsions whichare alkaline. Wlhen adding our sensitizers to such emulsions it isgenerally desirable to adjust the pH of the sensitizing solution so thatit will not seriously alter the pH of the emulsion to be treated.

The invention has been described in detail with particular reference topreferred embodiments thereof but it will be understood that variationsand modifications can be effected within the spirit and scope of theinven tion as described hereinabove and as defined in the appendedclaims.

We claim:

1. A polyfunctional polyalkylene compound and the correspondingpolyquaternary salt of said compound selected from the group consistingof those having the formula:

wherein R represents an alkyl group having from 1 to 20 carbon atoms; mis an integer of from 2 to 3; q and q each represent an integer suchthat the total of the 4 qs and Q1 has an average value of from 6 to Yrepresents a member selected from the class consisting of a hydroxylgroup, a

group and a group; R R and R each represents an alkyl group having from1 to 4 carbon atoms; and X represents an anion selected from the groupconsisting of a halide, perchlorate, a lower alkylsulfonate,toluenesulfonate and benzenesulfonate.

2. A polyfunctional polyalkyleneglycol compound selected from thosehaving the formula:

wherein n n n n 11 each represents an integer such that the total of n+n +n +n +n has an average value of from 6 to 100; Y is a memberselected from the class consisting of a hydroxyl group, a

Ff e

and 3.

(References on following page) References Cited UNITED NORMA S.MILESTONE, Primary Examiner.

A. L. ROT MAN, Assista'nt Examiner.

STATES PATENTS Blake 96-407 Piper US. Cl. X.R.

Beavers 96-108 5 260-295, 404, 404.5, 482, 501.15, 561, 567.6, 584, 401;Jones 96-107 96107, 108, 50

